Spectrum of enteropathogens detected by the FilmArray gastrointestinal (GI) panel in a study of travelers’ diarrhea – a completely new epidemiology

Background: Travelers' diarrhea (TD) is the most common illness among people traveling from resource-rich to resource-limited regions of the world. Nevertheless, the precise microbial etiology is not identified in many cases. The purpose of this study is to detect pathogens present in cases of TD using a multiplex PCR-based assay.

Methods: Prospectively collected stool specimens (n = 37) from patients diagnosed with TD were tested using the FilmArray gastrointestinal (GI) panel (BioFire Diagnostics) and conventional stool culture as a comparison method. The FilmArray GI panel can simultaneously detect 22 different enteric pathogens directly from stool specimens: Campylobacter spp., Clostridium difficile (toxin A/B), Plesiomonas shigelloides, Salmonella spp., Vibrio spp., Vibrio cholerae, Yersinia enterocolitica, enteroaggregative Escherichia coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), Shiga-like toxin-producing E. coli (STEC), Shigella spp./enteroinvasive E. coli (EIEC), Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, Giardia lamblia, adenovirus F 40/41, astrovirus, norovirus GI/GII, rotavirus A, and sapovirus.

Results: Fifty-six consecutive cases were included in the study. Twenty-seven cases had returned from travel in Southeast Asia, 14 from South Asia, 5 from Africa, and 3 from East Asia. Of the 56 specimens analyzed, 51 (91.1%) tested positive for pathogens, when the FilmArray GI panel was used, whereas 5 tested negative. Commonly detected pathogens were EAEC (50.0%), EPEC (35.7%), ETEC (30.3%), Campylobacter (21.4%), STEC (19.6%), Shigella/EIEC (17.9%), and norovirus GI/GII (12.5%). Multiple pathogens were detected in 69.6% of the specimens (mean number of pathogens detected = 2.27). In contrast, conventional stool culture detected pathogens in only 17.9% of specimens. All specimens that tested positive for pathogens in the conventional stool culture were also positive in the FilmArray GI panel.

Conclusion: The FilmArray GI panel significantly improved the detection of enteropathogens and allowed quick assessment of the etiology of TD. Additionally, conventional stool culture is likely to underestimate co-infections with multiple infectious pathogens.